Here's a
better look at the pattern. It appears to me that the block is 10 strips wide and two strips high. It has a 1/2 square triangle on the end of each of the four center strips, then the triangle gets longer and longer as it moves up the "mountain" on each side of the center. Then, in the next block, it moves down the "mountain" to the center block.
At least that is how I would describe it. I've found if you'll draw it on graph paper, you'll figure out how to do it. At least, that's how it works for me.
bkay